Richter Magnitude From Amplitude Calculator
Original Richter (1935) local magnitude ML = log10(A / A0), comparing maximum Wood-Anderson trace amplitude in millimeters with the zero-magnitude reference amplitude at the same epicentral distance (0.001 mm at 100 km by definition).
Description
Original Richter (1935) local magnitude ML = log10(A / A0), comparing maximum Wood-Anderson trace amplitude in millimeters with the zero-magnitude reference amplitude at the same epicentral distance (0.001 mm at 100 km by definition).
Richter Magnitude From Amplitude Calculator: Original Richter (1935) local magnitude ML = log10(A / A0), comparing maximum Wood-Anderson trace amplitude in millimeters with the zero-magnitude reference amplitude at the same epicentral distance (0.001 mm at 100 km by definition).
When to use Richter Magnitude From Amplitude
Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.
- Amplitude
- Maximum trace amplitude on a Wood-Anderson seismograph, in millimeters.
- Reference amplitude
- Zero-magnitude reference amplitude at the same distance, in millimeters.
How Richter Magnitude From Amplitude works
Original Richter (1935) local magnitude ML = log10(A / A0), comparing maximum Wood-Anderson trace amplitude in millimeters with the zero-magnitude reference amplitude at the same epicentral distance (0.001 mm at 100 km by definition). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.1
- ML
- Local (Richter) magnitude ML.
Limitations and assumptions
- Seismic magnitudes, moments, travel times, velocities, resolution, and energy depend on instrument correction, Earth model, phase picking, geometry, attenuation, radiation pattern, bandwidth, and calibration range. Magnitude scales are not universally interchangeable.
- Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.
Alternative or Complementary approaches
Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.
References
-
Seismology — Wikipedia contributors
Similar or alternative tools
- Gutenberg Richter B Value Calculator
Aki (1965) maximum-likelihood b value of the Gutenberg-Richter law log10 N = a - bM: b = log10(e) / (mean magnitude - completeness magnitude).
- Epicentral Distance Calculator
Great-circle epicentral distance from event to station via the haversine formula on a spherical Earth of mean radius 6371 km.
- Swell Index Calculator
Free swell index of a clay per IS 2720 Part 40: (V_water - V_kerosene) / V_kerosene * 100, comparing equilibrium volumes of equal dry specimens in distilled water versus kerosene. Volumes in mL.